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Question : 60 of 160
Marks:
+1,
-0
Solution:
PQ=3−2+2...(i)
PS=−2...(ii)
Eqs.
(i)+(i)⇒PQ+PS=4−2+0k PR=4−2 Eqs.
(i)−(ii)⇒PQ−PS=2−2+4 Eqs.
(i)−(ii)⇒PQ−PS=2−2+4 −QS=2−2+4 ⇒QS=−2+2−4 Let
θ be the angle between diagonal PR and
QS ∴cosθ= | (4−2)(−2+2−4) |
| √16+4+√4+4+16 |
== ==−√=−√ ∴cosθ=−√
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